The extraction of bitumen from oil sands has been traditionally performed using the Clark Hot Water Extraction (CHWE) process. A tailings slurry, defined as whole tailings, is produced as a byproduct of the CHWE process, and can include water, sand, clay, and residual bitumen particles that are suspended in the extraction process water. Coarse sand particles (e.g., >44 μm) can be easily removed from whole-tailings, but removal of finer particles (fines) can be more problematic. A portion of the remaining fines, water, and residual bitumen form a slurry that is about 10-15% solids by mass, which after a number of years can settle to be about 20-30% solids by mass. This slurry is referred to as fluid fine tailings (FFT) and/or mature fine tailings (MFT), and can remain for decades in a fluid state without further aggregation or settling. Slow consolidation, limited solids strength, and poor water quality of the FFT/MFT limits options for reclamation and has resulted in the formation of large tailings ponds.
A number of different technologies have been tried to improve the reclamation of FFT/MFT. Some of these technologies include whole-tailings treatment, non-segregating tailings (NST) production, composite tailings (CT) production, tailings reduction operations (TRO), atmospheric drying, or treatment with polymers. These methods, however, have worked with only limited success, as there currently exists over a billion cubic meters of FFT/MFT in tailings ponds. As such, there is a need for an improved method and process to treat oil sands tailings to provide an effective reclamation option.